The deleterious effects of ethanol and acetaldehyde on the contractile and regulatory proteins of muscle myofibrils have been established. The proposed studies will attempt to elucidate the effects of ethanol and acetaldehyde on similar contractile and regulatory protein systems isolated from purified preparations of hepatocytes and/or from whole liver tissue. The contractile protein system in liver tissue exists in a dynamic state by which the assembly and disassembly of their microfilamentous components most likely permit the hepatocytes to maintain their normal secretory and metabolic activities. Through the availability of calcium ions, ADP, and a phosphorylating enzyme system, the control of the assembly and interaction of actin-like and myosin-like structures is carried out by a regulatory mechanism similar to that found by us and others in various non-muscle tissues. We plan to determine the effects of ethanol and acetaldehyde on the properties and the interaction of the isolated components between themselves, leading to the reconstitution of these complexes on the surfaces of Lytron polystyrene particles under conditions that imitate their assembly and composition in the intact tissue. The ultimate goal is to be able to assess the parameters that are altered by chronic and acute ethanol consumption when these proteins are obtained from tissues of our animal models exposed to alcohol ingestion.